Retorting process and apparatus



April 18, 1961 R. F. DEERING ETAL 2,980,592

RETORTING PROCESS AND APPARATUS Filed June 19, 1958 2 Sheets-Sheet 1 97 fran/M April 18, 1961 R. F. DEERING ErAl. 2,980,592

REPORTING PROCESS AND APPARATUS Filed June 19, 1958 2 Sheets-Sheet 2 the unit.

` 2,980,592 RETORTING PROCESS AND APPARATUS Filed June 19, 1958, Ser. No. 743,085 1s Claims. (cl. 2oz-s) This invention relates in general to improvements in solids-Huid contacting, and particularly to an improved process and apparatus for the production of hydrogen gases and oils from solids by thermal means. Applicable solids include' such oil-producing and oil-containing materials as oil shale, tar and oil sands, oil-saturated diatomite, bituminous and sub-bituminous coals, and the like. For the sake of simplicity, the description will be conducted in terms of the eduction of shale oil and gas from oil shale, but it is to be understood that the process and apparatus are applicable in general to other processes in which oils and gases are produced by solidsfluid contact at elevated temperatures.

Of the various oil shale eduction processes which have been proposed, one of the more successful has been one in which the oil shale is passed upwardly countercurrently to a downow of eduction uid, an example of which is in U.S.l Patent No. 2,640,019.` This is used in combination with the present invention. The shale is fed upwardly and successively through a product fluidshale rock disengaging zone, `an eduction zone, a combustion zone and an ash Acooling zone, while air or other oxygen-containing gas i'svintroduced at the top of the ash cooling zone and passes downwardly through the aforesaid zones in reverse order. During such passage, the air is first preheated by cooling the hot shale ash in the ash cooling zone, and then Iburns thecarbonaceous 'residue from the spent shale in the combustion zone, thereby lforming hot flue gases and hot shaley ash. The hot'ue gases, which Aconstitute the eduction uid, continue downwardly to heat the shale rock to eduction temperatures'in the` eduction zone. Within the latter, hydrocarbon ,oils and gases are educted from the shale, fornling spent carbonaceous shale and a mixed uid phase containing liue gas and oil vapors and liquids. The fluid phase is cooled and passes downwardly in direct contact with the cool raw shale, thereby condensing the hydrocarbon oil and pre-heating the raw shale. The liquid and gaseous products are drawn off at the disengaging zone and are thus separated from the'upwardly moving shale rock. A solids feeder passes the shale rock upwardly through the disengaging and eduction zones, andv displaces the shale ash out the top of The process thus supplies its own fuel in the vform of carbonaceous spent shale, and cools and partially condenses its own product by preheating the cool raw shale.

Despite its superiority over the other oil shale eduction methods, the above process does present certain difficulties which are believed to be due to the presence of nes in the burning zone of such an upwardly moving bed. Fines in the burning zone increase the tendency toward sintering or slagging, resulting in the formation of4 large clinkers whichpreventeven. distribution of ai! 2,980,592 Patented Apr. 18, 1961 "wie 5 duced by undue agitation of ash during removal from the top of the bed, which ash fines then fall back into the burning zone.

An outwardly tapered retort from bottom to top such as is generally used in a solids upow process is also limited in oil shale throughput capacity by the burning zone area. Thus a burning zone contained within such a retort at a lower level results in a more limited retort capacity than if the burning zone were at a higher level. Furthermore, a burning zone within a retort shell produces greater Shell distortion due to high temperatures encountered. Shell distortion is undesirable because of mechanical difculties present when operating with a distorted shell, and because the shell distortion if attributed to the presence of lines in the solids treated.

vA still further object is to provide, in an oil shale eduction process of the upow solids type, means for improving the ease of temperature control and uniform distribution of the air and/or the eduction fluid.

We have now found that the foregoing objects and attendant advantages may be realized in -a process and apparatus in which the ash cooling (and air preheating) zoneand the combustion zone are maintained primarily above the top level of the retort shell, and the bed of solids above the retort shell is maintained in the shape of a truncated cone by means of a moving scraper or the like which is hereinafter more fully described. By the `foregoing means, the combustion zone area and retort capacity are increased, and uniformityof the rising solids mass above the retort shell is maintained. This has an effect of tempering slagging conditions in the combustion zone, reduces the production of fines, and reduces the ash content of Vthe product fluids. Furthermore, the maintaining of a uniform periphery of rising solids mass above the retort shell results in improved control over the temperature in the combustion zone, gives uniform rdistribution of the air passed into the rising solids mass, and gives a more uniform distribution of the eduction fluid throughout the rising solids bed.

The present invention is therefore directed to an improvedv upllow solids retorting process and apparatus in which the solids pass upwardly countercurrent to a downow of eduction fluid, and in which the burning of residual carbon on the educted solids and cooling of the resulting'ash 'to a large extent occurs above the top edge of the retort while maintaining the shape of the bed above the retort in/the general shape of a truncated cone.

In the accompanying drawings which form a part of this application:

Fig. 1 is an elevation view, in partial cross-section,v

fm the raming. Qt @il Shale, sndindisates at the upper eed,

, 3 thereof the rotary equipment employed to maintain a shaped bed of solids substantially `above the retort shell as previously mentioned.

Fig. 2 is an isometric view of the rotating scraper assembly shown in Fig. l.

Fig. 3 diagrammatically illustrates the configuration of the1 bed of rising solids adjacent t-hegtop of the retort, an

Fig. 4 is atop plan view of an alternative form of scraper assembly.

Referring now to Fig. l, the retort itself consists essentially of a `feeder case 10, a perforate solids-fluid disengaging section 12, and an eduction section14 superimposed one above the other in the manner iSllQwn.V A rotating scraper assembly is mounted abdveeduction section 14, and serves to maintain that portion of "the bed which extends above the top edge 13,3 iof the retort inthe general shape of a truncated cone. Y

Oil shale is introduced into feed Ahopper Y16 and isfed by means of a solids, feeder assembly upwardly successively through disengaging section 12 and 'eduction section 14. The solids feeder assembly comprises a solids feeder cylinder 18 disposed within feeder case 1t) kand supported by trunnion 20 which permits itto beoscillated in a Ivertical plane so that the upper opening `of the cylinder is aligned alternately with the bottom of hopper 16 and the solids inletto disengaging section 12. A hydraulic feeder cylinder 22, provided with piston rod 24 and feeder piston 26, Vis disposed within solids feeder cylinder 18 and oscillates with it. Guards or shoes 28 and 30 curve away from the sides of the upper opening of feeder cylinder 18 and serve to close the lower outlet of hopper 16 when feeder cylinder 1,8 is in the position shown, and

also to close the solids inlet to disengaging section 12` when the feeder cylinder is oscillated to the left in registry with hopper 16. The oscillatory motion of feeder cylinder 18 is provided by means of oscillating hydraulic cylinder 32 connected at pivot 34 to the inside of feeder case 10, and also connected at pivot 36 by meansY of piston rod 38 to the side of feeder cylinder 18.

The cyclic action of hydraulic cylinders 22 and 32 achieves removal of fresh solids from hopper 16 and the introduction thereof upwardly from below in a vertical path through disengaging section 12 and eduction section 14 in a sequence of four repeated steps. First, the oscillating hydrauliccylinder 32 retracts and pulls solids feeder cylinder 18'and hydraulic feeder cylinder 22 Vout of the position shown and to the left into alignment with shale hopper Y16. Second, hydraulic feeder cylinder 22 retracts feederk piston 26 downwardly toward trunnion 20, drawing a charge of fresh shale into the top of feeder cylinder 18, During this time guard 30 seals the solids inlet to disengaging section 12.` Third, hydraulic oscillating cylinder 312 extends, moving solids feeder cylinder 18'back into the vertical positionshown, but with feeder piston 26 at its lowest position, not shown. Fourth, feeder cylinder 22 extends moving feeder piston 26 upwardly forcing the charge of raw shale upwardlylinto the lower part of disengaging section 12. The entire mass of solids moves upwardly through sections 12 and 14 and educted solids discharge from the top of eduction section kv14. During this time guard 28 is in the position shown, closing the lower outlet of feed hopper 16. These four steps are repeated in sequence to maintain a substantially continuous upward flow of solids.

A pair of inclined sloping bafdes 40 and 42.are provided along the bottom of feeder case extending in the general direction of the plane of oscillation and closely beside trunnion 20, thus providing feeder case 10 with a V-shaped bottom. Along the lower line of intersection of the trough is extended screw conveyor 44, driven by conventional rotary means not shown. Conveyor 44 moves solids iines which leak past guards 28 and 30 and accumulate in the feeder-case to feeder vcase outlet48. Then lines, plus some product-oil are removed in the form of a slurry from outlet 48 and pumped by means of pump 50 through line'54 into the product separator chamber 64. From here, as described below, the fines are recycled to the shale feeder.

As indicated previously, the solids move successively in an upward direction as a dense, fluid-permeable, continuous mass through the perforated fluid disengaging section 12 and through eduction section 14. The downward countercurrent flow of air and eduction uid is maintained by means of blower 60 which takes suction through line 62 at the upper end of product separator chamber 64 surrounding the perforated disengaging section 12. Air therefore enters the open `top of eduction section 14 through the ash discharge apparatusv126ras described below, and passes downwardly through ash cooling and air preheating zone 66 into educted shale cornbustion zone 68. The ilue gases which are formed in cornbustion zone 68 and which constitute the eduction lluidv are drawn successively through retorting or eduction zone 70 and raw shale preheating and product fluid cooling and condensing zone 72, intoV disengaging section `12, and thence throughperforations 74 into separator chamber 64. The fluid products produced in the eduction zone are also drawn with the eduction fluid by blower 60, through preheating zone 72 and perforations 74 into product separator chamber 64. The condensed shale oil accumulates' in the lower portion of product separator chamber 64 providing a liquid ylevel atv the approximate position indicated at 76. The feeder case'10 is also filled withthis product oil.

Product separator chamber 64 is provided witha VV-` shaped bottom comprising two pairs of inclined baies, one of which `is indicated at 78j and the intersection lines of which run generally parallel to the Plane of Fig. 1. The baffles are inclined with respectto one another at angles` of about 45 when viewed inl a plane at 90 from the plan of Fig. l. Along the'bottom of each V-shaped pair of bales is extended a primary screw conveyor, one of which is indicated at 80. Conveyor 80 is vdriven by rotary drive means 82, and delivers any solid shale nes which fall through slots 74 and settle in chamber 6'4, into transverse secondary conveyor 84. The fines are here accumulated vfrom both primary conveyors and discharged by means `of conveyor 84 into fines distributor S6. The latter is designed to discharge the fines centrally at the bottomof shalehopper 1,6 so that the nesare concentrated inthe interior of the charge of larger sized shale particles into which they are introduced.v This reduces subsequent fall-through of these same nes into product separator chamber 64 and insures, that they be carried upwardly with the raw shale feed and treated therewith in eduction section 14. Notealso thatthe fines Withdrawn from feeder case outlet 48 v'and discharged'into separator chamber64 mingle with the nes passing out ofY slots 74 and are likewise recycled to the central portion ofthe feed hopper'16.

As indicated previously, the liquid and gaseous `components of the eduction product `are separated from each other in separator chamber 64. The liquidshale oilows from separator chamber 64 through line 86 under the inuence of product oil pump 88 at a rate controlled by valve 90 and liquid level controller 92.

Blower 60,;previously described, draws non-condensed gases throughline 62 from the upper portion of separator chamber 64 and passes them through 1ine96 intomist separator 98 at a rate controlled by valve 100. Pressure controller 102 may serve to control valve 100 in order to maintain a predetermined subatmospheric pressure in separator chamber 64, or it may, if desired, serve to tain a predetermined differential pressure between thetop and the bottom of eduction section 14. The flow rate of gas through line 96 in turn regulates shale feed rate which Vthen controls bed pressure differential and gas rate in the following manner. VFlow recorder controller operates in response to kgas ow rate inflinei96. With too .hghla gas rate through line 96, as a result'ofthe hig'h burning zone and lessfbed' fusion, ow recorder controller 95 controls pumpv 97 to reduce the rate at which hydraulic uid is supplied from source 99 tothe hydraulic cylinders 22 and 32, thereby reducing the shale feed rate. This tends to reduce the bed pressure differential and gas rate through line 96. Too low a gas rate through line 96, as a result of too low burning zone and bed fusion, operates by control of uid supply pump 97 to increase both shale'feed rate and bed pressure differential with an attendant elevation of the burning zone and fusion reduction thus increasing gas rate through line 96.

Any conventional pneumatic recorder controller system elements may be used to accomplish thevvarious control methods used above when the measured indicating variable is pressure or fluid ow.

In mist separator 98, residual traces of entrained liquids are separated from the gas stream and are passed l through line 104 controlled by valve 106 into combination with the `shale oil product produced through line 108. The non-condensed gases ow through line 110 provided with valve 1-12. These gases comprises ressentially carbon monoxide, nitrogenl and carbon dioxide with relatively small amounts of hydrocarbon gases suicient to give the gas a heating value ofabout 90-100 B.t'.u per cubic foot. Accordingly, it maybe used as fuel or, if desired, part or all of it may be reintroduced -as recycle gas into the top of eduction section 14 to dilute the incoming air in order tov moderate combustion temperatures and the conditionsY of eduction. VEduction sectional 14 is conical in shape, as is disengaging section 12, The eduction section 14 is provided on its outer surface with 'a plurality of vertically extending radial ns 114, the outer edges of Vwhich are enclosed in jacket 116.` Said fins and jacket thusform a series of vertical passageways which are open at their lower ends to Atlow of air by natural convectio'npsuchilow of air serves to cool the metal walls of' eduction 'section 14. The upper ends of the vertical passageways terminate in a manifold 119 which serves to collect the stream of warm air which flows upwardly through thev passageways and to discharge said streams to the atmosphere through one or more stacks not shown. v Hood 123, having outwardly aring sidewalls 124, is supported above the retort by means of a V-shaped mounting ring 125 which is rigidly aixed to the lower vedge of sidewalls 124 and retortjacket 116 as shown. The horizontally disposed portion of mountingr ring 125v is provided with two relatively largeapertures126, spaced 180 apart, and a rotary belt ash conveyor -127 is mounted immediately below4 eachof said apertures; Sidewalls 124 and mounting' ring' A125 extendv to' below the top edge 133 of the retort, and for'rn an annular chute through which theshale ash, which spills over the top edge of the retort, falls and passesthrough apertures 126 to ash conveyor 127. Rotary Scrapers', not shown, may be mounted within said chute to scrape the ash into apertures 126. Y

The eduction air, preferably at atmospheric pressure, is drawn upwardly through apertures 126 by blower 60, reverses its direction within hood 123, and passes downwardly through the rising bed of solids as previously explained. The air thus passes countercurrent to the hot shale ash sliding down through the chute, and is thereby preheated while cooling the ash. Such arrangement utilizes the heat of the ash and increases the overall thermal eiliciency of the unit.

The foregoing description indicates the general scheme of the upow solids-huid contacting process and apparatus. The following description, made with reference to Fig. 2 as well as Fig. 1 relates more particularly-to the operation and design ofthe scraper assembly which serves to maintainthe rising mass of solids 'which protrudes above top edge 133 of the retort in the general shape of a truncated cone.

6 "The-scraper assembly consist of 'a vertically disposed central shaft 200 having a horizontal platform 202 rigidly atlixed to its upper end. l A sloping scraper bar or 'leg 204 is rigidly aixed as by welding to the periphery of platform 202, and extends downwardly and outwardly therefrom so that its lower end lies closely adjacentto the top edge 133 of the retort. The anglewhich scraper bar 204 makes with the horizontal corresponds approximately to at least as great as the natural angle of repose of the ash. By natural angle of repose is meant the angle from the horizontal which would be assumed by size of the original shale. For Colorado shale ash this relatively cool, dry ash broken up to about the particle is about 35-45. v

A more nearly horizontal scraper bar 206, hereafter referred to generally as a horizontal scraper bar, is rigidly affixed to the -lower end of shaft 200 and extends radially outwardly therefrom to join sloping scraper bar 204 at a point substantially above the lower end of the latter. The vertical distance between the plane of horizontal scraper bar 206 and the top edge 133 of the retort determines the height to which the bed of shale ash protrudes above the edge of the retort, and such height is suitably of -the order of 1/5 the diameter of the bed. Platform 202, shaft 200, and the two scraper bars are caused 'to rotate by motor 208 mounted above hood 123 and connected to platform 202 via a reduction-gear unit 210 and shaft 212 which passes through the walls of hood 123 via bearing 214. As is readily apparent, rotation of the scraper assembly maintains the protruding bed of ash in the shape of a truncated cone. The speed of rotation will of course depend upon the rate at which the solids are passed upwardly through the retort, but under ordinary conditions of operation is of the order of 1-11 revolutions per hour for a' single blade 204. Scraping preferably is an infrequent as practical in' order to re; duce ash agitation.- A multiple blade arrangement, lof course, may be rotated more slowly to accomplish the same number of scraper contacts. n Y

Referring now to Fig. 3, there is shown a diagrammatic representation of the rising bed of solids in the upper part of the retort. As previously stated, an'important feature of the process of the invention lies in maintain# ing a` substantial part ofthe combustion and cooling zones above the top edge 133 of the retort. Thus, as shown in Fig. 3, the eduction zone 70 extendsup toja level approaching that of top edge 133, and burning or combustion zone 68 is of somewhat concave-convex extending substantially above top edge 133. Ash cooling zone 66v lies substantially entirely abovethe edge of the retort. .This configuration of the various zones'with in the rising solids bed results in greatly improved operation. A large part of the combustion occurs beyond the walls of the retort, and as a result such walls are not subjected tothe relatively high temperatures previously encountered. Typically, the .wall temperature is of the order of 800 F. or even less. The walls are thus subjected to less thermal stress, and their tendency to warp out of shape is minimized. Also, it has been found that the formation of fmes within the retort itself by attrition of the peripheral particles of the bed against the vwalls of the retort is considerably decreased when such walls are maintained at a relatively low`tempera ture. l

The position, and to some extent the shape, of the combustion zone within the shale bed is determined by the air-to-shale ratio. At a given rate ofshale feed, an increase in the rate at which the air is drawn downwardly through the bed will cause the combustion vzone to move downwardly andv its thickness to be increased. Conversely, by decreasing the rate of air feed, the combustion zone can be caused to become thinner and to move upwardly until it is positioned largely'above the level of the retort walls. Accordingly, it is, an important feature of the present process to control them-'toshale ratio in such manner that a substantial portion of theombustion zone lies above the edge of the retort. Typically. with a Colorado oil shale of V30 gah/ton FischerV assay, such air-to-shale ratio is of the order of 12,000 s.c.f./ton. Referring now to Fig.V 4, the alternative form of the scraper assembly there shown consists of a circular supporting plate 400, having a ring gear or a sprocket 402 axed at its periphery. A coaxial mounting plate 404 is aixed to the underside of supporting plate 400. Three sloping scraper barsV 406e, 4061 and '406C are rigidly aixed 120 apart to the periphery of mounting plate 40.4. .'I'hree more nearly horizontal outwardV sloping scraper bars 408a, 40811 and 408e extend between centralshaft 41.0, and sloping scraper bars 406:1, 406b and 405. respectively. The disposition-of the sloping and horizontal vscraper bars, and the manner in which they are afxed to their supporting structure is essentially the same as that. shown in Fig. 2. The assembly of Fig. 4 is rotatedjby a driven pinion engaging the gear ring, or by a drivenv chain engaging the sprocket. v As will be apparent to those skilled in the art, the scraper assembly may take various forms other than those described above, and the best manner for supporting the `scraper bars and causing them to rotate will be dictated by the usual engineering considerations based on the details of the retort construction, the physical characteristics of the solids being retorted, the ash, the temperature of the hot ash in which the Scrapers operate, and'similar operating variables. Essentially, the scraper assembly comprises one or more scraper bars disposed at'an angle' corresponding toan angle at least as great as the angle of repose of the ash, one or more horizontal scraper bars, means for rotating said scraper bars, and supporting means' maintaining said scraper bars in such position that upon being rotated they ,trim the mass of rising solids above the top edge of the retort-into the shape of a truncated cone.

A typical example of a retorting operation on Colorado oil shale assaying 30 gallons/ton with the process and apparatus of the invention is as follows:

Raw oil shale: Fischer assay, gat/ton 30 Particle size, inches J/z to 3 Mineral, CO2, wt. percent 18 Crude shale oil: Gravity, API 2l Yield, vol. percent RA. 80 Retort make gas:

Quantity, s.c.f./ton 18,000 Cross heating value, B.t.u./s.c.f. 98 Design` factors: Retorting rate, lb./ (hr.) (sq. ft.) 300 Air, s.c.f./ton 12,000

Gas and oil outlet temperature, F. 125 Ash chute outlet temperature, F. 900 Scraper slope- Lower scraper (three blades) 40 Upper scraper (three blades) Horizontal Scraper rotational rate, r.p.h. 2

Use of the process and apparatus of the invention effects a number of improvements in the retorting operation. For a shell of given maximum diameter at its upper periphery there is a greater burning area and a resultant greater throughput with the foregoing process and'apparatus. That is, this is true when the comparison is made with a similar shell having a lower burning zone. Thus, the economic advantage over heretoforeknown commercially practical process and apparatus is greatly increased because of increased throughput rate.

TheA ash is more gently handled than permitted by a ash bed vandproduction ofV ne's' vby attrition of ash dragged against-ash 'for extensive distances.y Such vproduction'offines-having been substantially avoided thus reduces `resultanit clinkering in the burning zone.' Clinkering when present Vtoa greater extent results in a 4decrease `in .retorting capacity and an increasev in requirements on the main blower, such as 60. rThere arethus appreciable economic savings ron main 'blower requirements as wellas further increased througput for a giveny narily fail.

ilat type bed scraping at the kiln top level. The-ash for the. mostpart doesnthave to be dragged as far across .the-ssh; 'brd- This substaafisllravvids stirrinstlp of the Continual movement in rotary motion over the central areas of the ash bed prevents a dead zone which in such an upward solids ow retort frequently develops. Such a dead zone is a bed area in which solids dwell an undesirable length of time, which because of the heat of the burning` zone below, then forms clinkers in the dead zone, or within the burning zone below it. Also, the continual movement over the bed by the scraper apparatus of the invention doesy not in any way restrict up-l ward movement of vthe -upwardly moving solids and ash bed from below Abecause-of the small contacting surface area of thescraperwith the ash` bed over any particular bed -area for any great lengthof time.

With the process and scraping apparatus of the present invention, lower bedpressure differentials are required at comparable throughput rates than for any type retorting unit not employing such. A lower bed pressure differential results in appreciable savings in blower horse power requirements for creatingA thepressure differential, which lowers. considerably initial cost of the gas blower.

Particular embodiments of the present invention have been described above in considerable detail by way of illustration. It should be understood that various other modifications and adaptationsthereof may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims which dene ythe limits of the present invention.

We claim:

1. In an apparatus for passing solids upwardly through a kiln and removing ash from thetop thereof, the improvementwhich, comprises a scraper bar inclined at an angle from horizontal, and extending from a point adjacent the upper peripheral limit of said kiln upwardly toward the upward extension of the center line of said kiln, a more, nearly horizontal scraper bar extending yfrom said inclined scraper bar to said upward extension of the centerline of said kiln, a rotatable supporting means positioned above said kiln and supporting said inclined scraper bar and said more nearly horizontal scraper bar in respective positions above said contacting apparatus and motive means for horizontally rotating said rotatable supporting means.

2. Apparatus according to claim 1 in which said rotatable supporting means comprises a dependent rotatable shaft coincident with said upward extension of the centerline of said kiln and engaged with said motive means.

3. Apparatus according to claim 1 in which said 4rotatable supporting means comprises a rotatable circular supporting plate provided with means for engaging said motive means vfor rotating said rotatable supporting means.

4. Apparatus according to claim Al in which said nclined scraperbanis ,inclined atan angle .of at least 35 but less than 60 from horizontal.

gestisce 9 5. Apparatus according `to claim 1 in which said inclined scraper lbar is inclined at an angle of at least 35 but less than 45 from horizontal. v k

6. In an apparatus for the contacting of uids and shale solids which comprises a contacting vessel having an imaginarycenter line, a perforate uid disengaging vessel, and a solids feedery casedisposed at successively lower levels ina column, va-.shale-inlet hopper opening downwardly into the top of said feeder case, an oscillating vertically-acting piston solids feeder disposed in said feeder case, means for oscillating and reciprocating said piston feeder so as to receive a mass of shale solids from said hopper and force it upwardly into and successively through said disengaging and contacting sections, a closed separator vessel surrounding said disengaging vessel, and means for removing fluids therefrom to maintain flow of fluid downwardly through the rising mass of shale solids, the improvement in combination therewith of means for scraping the solid mass which rises above said contacting vessel, which comprises a scraper bar inclined at an angle from horizontal, said inclined scraper bar being so disposed as to extend from adjacent upper peripheral limits of said contacting vessel at a lower elevation toward a position which is on a point of an upward extended center line of said contacting vessel at a higher elevation, and which also comprises a more nearly horizontal scraper bar so disposed in positions as to extend from said inclined scraper bar to said upward extended center line of said contacting vessel, a rotatable supporting means supported above said contacting vessel for supporting said inclined scraper bar and said more nearly horizontal scraper bar in positions above said contacting vessel, and motive means for rotating said rotatable supporting means, whereby rotation of said rotatable supporting means rotates said scrapcrs and scrapes olf said rising mass of solids above said contacting vessel in the form of a uniformly truncated conical shaped mass having a minimum diameter at a central higher elevation and having a maximum diameter at a lower elevation at the upper periphery of said contacting vessel.

7. In an apparatus for the contacting of uids and solids which comprises a contacting vessel, a perforate fluid disengaging vessel, and a solids feeder case disposed at successively lower levels in a column, an inclined solids inlet hopper opening downwardly into the side of said feeder case, an oscillating vertically-acting piston solids feeder disposed in said feeder case, means for oscillating and reciprocating said piston feeder so as ot receive a mass of solids from said hopper and force it upwardly into and successively through said disengaging and contacting sections, a closed separator vessel surrounding said disengaging vessel, and means for removing uids therefrom to maintain ow of uid downwardly through the rising mass of solids, the improvement in combination therewith of means for scraping the solids mass which rises above said contacting vessel which comprises a first scraper bar inclined at an angle from horizontal and positioned to extend from the upper peripheral limits of said contacting vessel at a lower elevation toward an extended center line of said contacting vessel at a higher elevation, a second scraper bar substantially horizontal in position extending from said first' scraper bar to said extended center line of said contacting vessel, means of support for said rst and second scraper bars in said positions, rotatable means for rotating said first and second scraper bars and their means of support concentrically with respect to said extended center line of said contacting vessel, and motive means for rotating said rotatable means and two related scraper bars, whereby movement of said irst scraper bar scrapes olf said rising mass of solids at an angle from horizontal at the elevational periphery of said rising solids mass thereby releasing the scraped off portion of said peripheral solids 10 and movement of said ysecond scraper bar levels the cen-1 tral topmost area of said rising mass of solids to 'move solids from the central topmost areatothe elevational periphery of the rising solids mass where said first scraper bar operates. l

8. A scraper assembly mounted on and positioned above a `kilnfand adapted for scraping a mass of rising solids above the v'top edge .of4 said kiln comprising: at least one inclined scraper .bar extending inwardly and upwardly from the kiln upper edge at an angle from the horizontal at least as great as the angle of repose of said solids; a vsubstantially horizontal scraper bar extending from said inclined scraper bar to a position above the center of said kiln; means for supporting and means for rotating said scraper bars in said positions whereby a truncated conical mass of rising solids is shaped above the upper edge of said kiln.

9. .Apparatusv according to claim 8 in which said kiln is adapted for contacting of uids and shale solids, said kiln assembly comprising: an upper contacting vessel, an intermediate perforate uid disengaging vessel, and a lower solids feeder case, an inclined shale inlet hopper opening downwardly into the side of said feeder case, an oscillating vertically acting piston solids feeder disposed in said feeder case, means for oscillating and reciprocating said piston feeder so as to receive a mass of shale solids from said hopper and force it upwardly into and successively through said disengaging and contacting sections, a closed separator vessel surrounding said disengaging vessel, and means for removing uids therefrom to maintain a ow of uid downwardly through the rising mass of solids.

10. Apparatus according to claim 8 in which said scraper bar supporting means comprises a moveable circumferential ring support situated and supported about the upper periphery of said kiln.

11. Apparatus according to claim 8 in which said scraper bar supporting and rotating means comprises: motive means, a central rotatable shaft operatively connected to said motive means and positioned above and on an extended centerline of said kiln and means for i joining said scrapers to said central shaft.

12. In a method for continuously processing solids, wherein said solids are passed upwardly through a solids bed containing a processing zone to which heat is supplied by direct contact with a downwardly owing stream of combustion gas from a combustion zone maintained at a higher zone within said bed of solids, the improved method of maximizing vessel capacity and minimizing thermal stress of said vessel walls, which comprises permitting said bed of solids to rise above the upper edge of the vessel, supplying combustion supporting uid downwardly through the upper surface of said rising mass, and continuously scraping the upper surface of said rising mass to shape said mass into a form which will permit the downwardly introduced combustion supporting fluid to be uniformly distributed over the cross sectional area of said bed of solids and maintaining a substantial vportion of said combustion zone above said upper vessel edge and within said rising mass of solids.

13. A method according to claim 12 in which the solids processed are shale :and the combustion supporting fluid is air.

14. A method according to claim 12 in which the rising mass of solids is scraped into a truncated conical shape.

15. A method according to claim 14 in which the elevation of saidtruncated cone above said vessel is at least 10% of said kiln diameter but not more than 45% of said kiln diameter.

16. A method according to claim 14 in which said combustion-supporting luid is air at atmospheric pressure and is uniformly drawn into said truncated cone at sefor removal by gravity from the vicinity-of the apparatus, lected rates of volume by providing selected subatmoephefic pressuresat a lower elevatio'n of said rising massy af. sclids. y

least 5% of said kiln diameter but not more Ythan l45% of said kiln diameter.

18.y A` method according to claimr 17 in which the maximum elevation ofv saidv truncated cone is not more than 30% of said kilndiameter.

References Ctedin the ile of this patent NITEDSTATES PATENTS Y Baneld\ June 7', 1938 Berg. t. Mar; 2l, 1950- BergA May y26, 1953 Berg n May 26, 1953` Holz et al. 4June 30, 1959 

12. IN A METHOD FOR CONTINUOUSLY PROCESSING SOLIDS, WHEREIN SAID SOLIDS ARE PASSED UPWARDLY THROUGH A SOLIDS BED CONTAINING A PROCESSING ZONE TO WHICH HEAT IS SUPPLIED BY DIRECT CONTACT WITH A DOWNWARDLY FLOWING STREAM OF COMBUSTION GAS FROM A COMBUSTION ZONE MAINTAINED AT A HIGHER ZONE WITHIN SAID BED OF SOLIDS, THE IMPROVED METHOD OF MAXIMIZING VESSEL CAPACITY AND MINIMIZING THERMAL STRESS OF SAID VESSEL WALLS, WHICH COMPRISES PERMITTING SAID BED OF SOLIDS TO RISE ABOVE THE UPPER EDGE OF THE VESSEL, SUPPLYING COMBUSTION SUPPORTING FLUID DOWNWARDLY THROUGH THE UPPER SURFACE OF SAID RISING MASS, AND CONTINUOUSLY SCRAPING THE UPPER SURFACE OF SAID RISING MASS TO SHAPE SAID MASS INTO A FORM WHICH WILL PERMIT THE DOWNWARDLY INTRODUCED COMBUSTION SUPPORTING FLUID TO BE UNIFORMLY DISTRIBUTED OVER THE CROSS SECTIONAL AREA OF SAID BED OF SOLIDS AND MAINTAINING A SUBSTANTIAL PORTION OF SAID COMBUSTION ZONE ABOVE SAID UPPER VESSEL EDGE AND WITHIN SAID RISING MASS OF SOLIDS. 